Reboring tool



L. M. BOATMAN REBORING 'rooL' Aug. 4, 1925.

File d Sept. 14. 1923 ATTORNEY.

Patented Aug. 4, 1925..

NITED STATE LLOYD M. BOAT'MAN, 0F NETMAHA, NEBRASKA.

REBORING TOOL.

Application filed September 14, 1923. Serial No. 662,742.

To all whom it may concern:

Be it known that l, LLOYD M. BOATMAN, a citizen of the United States, residing at N emaha, in the county of Nemaha and State of Nebraska, have invented certain new and useful Improvements in Reboring Tools, of which the following is a specification.

My invention relates to a reboring tool for engine cylinders.

My object is to provide a device of this character having a suitable cutter provided with a guide which fits the cylinder both in advance of the cutter and also after it, so that the rebored hole forming the inside wall of the cylinder will be exceptionally true.

Another object is to provide a device of this character which will readily clear itself of the shavings or cuttings bored from the cylinder, so that the cutting edge of the knife can always be kept clean and free from the accumulation of borings around it.

Another object is to provide a device of i this character which while very simple in its construction, will yet provide such a strong and positive guide for the cutter,

and will hold it so true to its work, that in the subward end portion in advance of the cutter of a size to fit the opening to be rebored, and the portion following the cutter of a size to fit the rebored part of the opening.

The invention consists in the novel construction and arrangement of the several parts, as will be hereinafter described and claimed, reference being had to the acconr panying drawings, in which I Fig. 1 is a vertical section through one of my devices.

Fig. 2 is a side elevation on a reduced scale of the device arranged for boring by hand; and, Fig. 3 is a view, on a still further reduced scale, illustrating means for holding the device to its work when reboring by hand.

Referring further to the drawings, the numeral 1 indicates a guide cylinder having an interior wrist pin 2 for revolving the cylinder. This wrist pin may be either rigidly connected to the cylinder or may be formed integral therewith. Rigidly or integrally connected to the wrist pin midway between its ends is a key post 3 adapted to be engaged by a universal joint 4 carried on a power shaft 5. The lower portion 4 of the universal joint is removably connected with the key post 3, in any suitable mann-er.

Suitably mounted on top of the wrist pin 2 is a tool post 6 of ordinary or preferred construction, having a set screw 7 for securing the tool 8 in operative position.

The lower portion 1 of the guide cylinder, which extends up to. the under side of he cutter 8, is of a diameter equal to that of the hole to be rebored, while the upper portion 1 is of a diameter equal to that of the cylinder after it is rebored; so that my guide cylinder fits the hole that is being rebored, both in advance of the cutter 8 and also following it. v

The portions l and 1" of the cylinder are connected together by an inclined annular shoulder 1.

The guide cylinder is provided in its wall with an opening 9 through which the cutter 8 projects to engage the work. The rear side of the cutter rests against the rear wall of the opening, with the opening practically in front of the cutter, so to speak, which permits the particles of displaced metal to fall through said opening to the inside of the guide cylinder; and as this cylinder is made with both ends open, the borings easily fall out through either end thereof, thus keeping the edge of the cutter clean and free from any accumulation of borings. It will also be seen that this arrangement keeps the tool from springing from its work or from chattering, so that an unusually true bore is made by the cutter.

In adjusting the cutter to its work, all that is necessary is to hold a vertically disposed straight edge on the portion 1 of the guide cylinder in the path of the cutter, and then move the cutter out into engagement with the straight edge. Such a straight edge is indicated in dotted lines in Fig. 2 being designated by the numeral 10.

The ease with which this adjustment is made presents a tremendous advantage over those cutters which have to be adjusted in pairs on opposite sides of a guide cylinder, since it is very difficult to get any a handle 12 on its upper end, and a rigid block 13 on its lower end for engagement with the universal joint which is the same asthat employed in the power driven tool illustrated in Fig. 1. Vi ith this form of the device I may employ a fork l lwhich can be entered in the valve seat in a Ford block when reboring a Ford cylinder by hand. Otherwise, the fork 14 may be omitted.

Whether I rebore by power or by hand, I prefer to employ the universal joint construction, as it causes the guide cylinder 1 to easily and accurately centre itself relatively to the hole that is being rebored, as well as adjusting it to the power bar 5, which with my construct-ion does not have to be adjusted into perfect alinemen-t with the longitudinal centre of the cylinder, but will work all right whether it is perfectly adjusted or not.

My device will usually be operated on" a.

power press in a vertical position, but it will also work well on a lathe in a horizontal position whenever it is found necessary or desirable to use it in that way.

Referring to the modification illustrated in Fig. 3 of the drawings, the threaded shank 11 passes through a cooperating threaded opening at 15 in the shank support 16. This support 16 has its two ends bent downwardly forming tl1e'sections17 and My construction entirely- 18, the section 17 terminating ina single foot 19, and the section l8terniinating in a doublefoot 20. These feet are provided with set screws 21, the single foot having one, and the double foot having two. By

means of these screws the support 16 is" rigidly secured to the top of the block, so that the tool willwbe held perfectly steady and true.

I provide the threaded shank 11 with.

very fine threads, to cause it to feed slowly to the Work, and thereby give a very fine bore.

by Letters Patent is A device. of the character described, comprising an integral guide cylinder having means therein for supporting a cutter; and means integral with the cylinder for connection with a drive shaft, said cylinder having an ample opening in its side for the cutter to extend out through to the work, and for the easy escape ofborings into the interior of the cylinder, the rear side of the drive shaft being located in advance of the centre of the cylinder in the guide part of Having thus described my invention,- what I claim as new and desire to protect the'cylinder, whereby the forcewhiclr drives and guides the cylinder is a plied at a oint' e centre 0 I the materially in advance of t cylinder.

In testimony whereof I affix my Sig LLOYD M. B-OATMANQ 

